Thread-clamp for sewing-machines.



F. A. READ.

THREAD CLAMP FOR SEWING MACHINES.

APPLICATION FILED NOV. 19. 1914.

Patented Sept. 5, 1916.

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WiTnesses.

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; ears aann'r Ff FRED A. READ, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THEREECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, ACORPORATION OF MAINE.

THREAD-CLAMP FOR SEWING-MACHINES.

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Specification of Letters Patent.

Patented Sept. 5, 1916.

Application filed November 19, 1914. Serial No. 872,902.

To all whom it may concern: Be it known that I, FRED A. READ, a citi--zen of the United States, residing at Lynn,

county of Essex, State of Massachusetts, have invented an Improvement inThread- Clamps for Sewing-Machines, of which the following description,in connection with the accompanying drawing, is a spec1fication, likecharacters on the drawing representing like parts.

This invention has for its ob ect to provide a novel thread clamp forholding the end of the needle thread so that when the stitchingoperation is started the first stitch will be properly formed withoutdanger that the end of the needle thread will be drawn through thefabric.

My invention is capable of use with sewing machines of different types,but I have herein illustrated it as it might be embodied in a so-calledReece buttonhole sewing machine. Examples of the Reece buttonhole sewingmachine may be found in the following United States Letters Patent: No.491,280, March 28, 1893; No. 655,637, August 7, 1900; No. 1,019,677,March 12, 1912.

Buttonhole sewing machines of this type embody work-holding means inwhich the work is clamped, and stitch-forming mechanism including upperthread mechanism and coinplemental under thread mechanism by which thebuttonhole stitches are formed, said stitch-forming mechanism beingcarried by a suitable frame. When the machine is set in operation, thework-holding means and stitch-forming mechanism have a movement relativeto each other to bring the stitch-forming mechanism and work-holdingmeans into such relative position that the stitches will be properlyformed on the buttonhole, this being referred to as the stitchingposition, and during the stitching operation said work-holding means andstitchforming mechanism have a further relative movement which is in thenature of a feeding movement to cause the stitches to be progressivelymade along the edges of the buttonhole. When the buttonhole has beencompleted, the stitch-forming mechanism is brought to rest, and saidstitch-formmg mechanism and work-holding means have a further relativemovement to bring the parts into their initial position.

Sewing machines of the above type are provided with buttonhole-cuttingmechanism which operates to cut the buttonholeeither before or after thestitching operation. The cutting of the buttonhole is accomplished whenthe stitch-forming mechanism and work-holding means have a relativeposition different from that in which the stitching operation isperformed, and which position will be referred to as thebuttonhole-cutting posltion.

When the machine has been brought to rest at the end of the stitchingoperation, the stitch-forming mechanism and workholding means are inbuttonhole-cutting position, and when the machine is first started, thework is clamped by the work-holding means, and if the machine is onewhich cuts the buttonhole before the stitching operation, the buttonholewill be cut, after which the stitch-forming mechanism and work-holdingmeans have a relative movement to bring the parts into stitchingposition. The stitchforming mechanism is then set in operation and saidstitch-forming mechanism and work-holding means have a relative feedingmovement to provide for the formation of the edge stitches around thebuttonhole, and when the stitching has been completed, thestitch-forming mechanism is brought to rest and said stitch-formingmechanism and work-holding means have a further relative movement tocarry them into buttonhole-cutting position again, at which time themachine is brought to rest.

When the stitching operation is first started it is customary for theoperator to hold the end of the upper thread which is controlled by aneedle while the first stitch is being formed in order that at the firstthrust of the needle a loop may be properly formed in the upper threadwith which the under thread may be concatenated. If the end of the upperthread is not held either by the operator or some suitable means itfrequently happens that the said end will be drawn through the cloth,thus destroying the loop with which the under thread is to beconcatenated. If this occurs the first stitch will be spoiled. I haveprovided herein a novel device by which the end of the upper thread maybe held during the formation of the first stitch, and in the selectedembodiment of my invention this thread-holding device is associated withthe work clamp, although this is not essential to the invention.

1 eye-pointed needle, and also includes comple- In order to give anunderstanding of my invention I have illustrated in the drawings aportion of a buttonhole sewing machine of the Reece typeto which myinvention is applied. V

section on substantially the line-0a-a2, Fig. 3.

In thesewing machine herein illustrated, the st1tch-forming mechanism issustained on a frame l which for convenience will be hereinafterreferred to as the stitch frame.

This stitch-forming mechanism includes the usual upper thread mechanismin the form of a reciprocating needle bar 2 carrying an meiital'underthread mechanism which is not herein illustrated as it is not necessaryto give an understanding of the invention.

The work-holding means is herein shown In the form of a clamp frame 3'onwhich the work is supported and work clamps 5 thatare supported by arms4 that are pivotally' secured to the clamp frame 3 to permit the clampsto move toward and from the clamp frame thereby to clamp and unmove thevparts from b'uttonhole-cutting poclamp the'work. The stitch frame 1withits stitchforming mechanism and the workholding means areconstructed to be moved relative to each other, as above described, to

sition'to'stitching position and vice versa, andalso to provide thenecessary feeding movement during thef stitching operation.

The means for giving the parts such rela- I tive movement are or may beall as illustrated in the above-mentioned patents and hence I have notdeemed it necessary to furtlierillustrate or. describe it herein.

' i'arovided witha'needle thread cutter 6 which ,is mounted on arock-shaft v7 journaled in Q'The sewing machine herein shown is alsobearings 8 carried by the stitch frame,*saidrock-shaft being providedwith an arm 9 1whi'ch is engaged by a finger 10 formed on the'igear 11by 'which the. upper thread mechanism is rotated thereby tocause the'cuttei dto sever the upper thread at the end of I the stitchingoperation on a button- Qhole. This thread cutter is similar to that*illustratedin *United States Patent-- No.

"forms nopart of thepresent invention, further description' thereof isnot necessary.

E'Fig. l illu tratesin full lines the relative position of thestitclrforming mechanism .and'jwork-holding'meansat the time thatthe-sewing machinefis at rest, this position being referred to as thebuttonhole-cutting I position. Then the machine is first started,

the work clamps 5 are brought into engagement with the work to hold itfirmly while the buttonhole is being stitched, and if the machine isequipped with a buttonhole-cutting device that is designed to cut thebuttonhole before the stitching operation, such cutting device will beactuated to perform its duties. The stitch frame and the worklioldingmeans are then given a relative movement to .carry ,them frombuttonholecutting into stitching position, and when they are institching position the stitchforming mechanismtis set in operationthereby to form the edge stitches of the buttonhole. The dotted lineposition in Fig. 1 shows the relative position of the stitchformingmechanism and the work-holding means when they are in stitchingposition. lVhen the stitch-forming mechanism is set in 7 operation theupper and under thread mechanism will operate on the work held by thework clamps to concatenate the edge stitches of the buttonhole, duringwhich time the stitch frame and work-holding means or clamp frame aregiven a relative feeding movement. When the stitching has been completedaround the buttonhole, the stitchforming mechanism is brought to restand at this time the stitch-forming mechanism has a position relative tothe clamp frame indicated approximately by the dotted line positionFig. 1. Thereafter, the stitch frame with its stitch-forming mechanismand the clamp frame or work-holding means have a further relativemovement to bring the parts intobuttonhole-cutting position whichisindicated by the full lines in Fig. 1. It is during this latterrelative movement of the gstitch frame and the clamp frame orworkholding means from stitching to buttonhole-cuttingposition that thethread cutter G is operated to sever the'needle thread beneath theclamps 5 which it will be under-' stood has been raised from the workafter the buttonhole has been stitched.

My improved thread clamp is designed to seize and clamp the portion 13of the upper thread 12 which extends between the needle and the workjust after the completion of the stitching operation on any buttonholeand while the stitch frame and clamp frame or work-holding means arehaving their relative movement from stitching to buttonhole-cuttingposition. My thread clamp is also preferably designed to hold the needlethread after it has been severed and until the stitching operation onthe next buttonhole begins,thus enabling the first stitch to beperfectly formed without any waste of thread such as results when theoperator draws out the end of the needle thread to hold it. The threadclamp as herein shown comprises a body portion 14- adapted to be securedto one of the clamps 5, said bodyl portion having for this purpose alaterallya t! at leaf spring.

surface 20 a flaring throat into which the end 13 of the needle threadcan enter. 21 is an adjusting screw which is screw-threaded into thebody 14 and engages the plate 17 thereby to limit the movement of theclamping plate toward the body and to regulate the clamping pressure ofthe clamp on the thread. I

When the sewing machine is in operation stitching the buttonhole theneedle for the upper thread is operating in the position shown in dottedlines Fig. 1 which is in the rear of the thread clamp. When thebuttonhole stitching has been completed, the stitch frame and clampframe have the relative movement above referred to to bring the partsinto the full line position Fig. 1, and during this movement the portion'13 of the upper thread 12 which extends from the needle to the workwill be carried into the flaring throat of the thread clamp formed bythe portion 19 and curved edge 20 and will be carried into the spacebetween the plate 17 and the body 1 1 and thereby clamped. The knife 6is then operated to sever the thread below the clamp and the clampretains its grip on the severed end of the thread while the machine isbrought to rest and until the machine is set in operation again and thefirst stitches of the next buttonhole are formed. The grip of the clampon the end of the needle thread is sufficient to cause the first stitchof the next buttonhole to be properly formed, and as the stitching onthe next buttonhole continues the end of the thread will be pulled outfrom the clamp, as will be obvious. The adjusting screw 21 provides, asstated above, for regulating the clamping pressure on the end of thethread to correspond to the tension on the thread and the size of thethread, etc.

While I have illustrated herein a selected embodiment of my invention, Ido not wish to be limited to the constructional details shown, as theform which the invention as sumes may be varied, and the manner in whichit may be applied to sewing machines may also be varied, depending onthe charactor of the machine.

I claim:

1. In a buttonhole sewing machine, the combination with stitch-formingmechanism, of work-holding means, said stitchforming mechanism andwork-holding means having a movement relative to each other subsequentto the completion of the stitching operation on a buttonhole to bringthe parts from stitching to buttonhole-cutting position, and a needlethread clamp carried by the won-holding means and located in such aposition that the needle thread is drawn into said clamp during therelative movement of the parts from stitching to buttonhole-cuttingposition.

2. In a sewing machine, the combination with-a stitch frame carrying areciprocating needle, of a clamp frame, said frames havmg a movementrelative to each other in a direction at right angles to the movement ofthe needle after the needle has been brought to rest upon the completionof a predetermined stitching operation, a work clamp secured to theclamp frame, and a needle thread clamp carried by the work clamp in sucha position that said relative movement of the frames will cause theportion of the needle thread extending from the needle to be carriedinto the thread clamp.

3. In a sewing machine, the combination with a stitch frame carrying areciprocating needle, of a clamp frame, said frames having a movementrelative to each other in a direction at right angles to thereciprocating movement of the needle after the needle has been broughtto rest upon the completion of a predetermined stitching operation, awork clamp secured to the clamp frame for movement relative thereto, anda needle thread clamp carried by the work clamp and havin an openthread-receiving throat positioned so that such relative movement of theframes will cause the portion of the needle thread extending from theneedle to the work to be carried into said throat.

1-. In a sewing machine, the combination with a clamp frame, of a workclamp movably supported thereby, a stitch frame carrying a reciprocatingneedle and having a movement relative to the clamp frame subsequent tothe completion of a predetermined stitching operation, and a needlethread clamp secured to the work clamp and so situated that the needlethread is drawn into it by said movement of the stitch frame.

5. In a buttonhole sewing machine, the combination with stitch-formingmechanism and work-holding means having a movement relative to eachother subsequent to the completion of the stitching operation on abuttonhole to carry the parts from stitching to buttonhole-cuttingposition, of a needle thread clamp carried by the work-holding means andpresenting an open throat so situated that the needle thread is drawninto it by such relative movement.

6. In a sewing machine, the combination with a stitch frame carrying areciprocating needle, of a clamp frame, said frames having a movementrelative to each other after the completion of i a predeterminedstitching operation, a thread clamp secured to the 'clamp frame andcomprising a body member and a clamping plate resiliently held againstthe body member and presenting therewith an open throat so situated thatthe needle thread is drawn into it by such rela 'tive movement of theframes, and means to needle, of a clamp frame,'said frames having amovement relative to each other after the completion of a predeterminedstitching operation, a thread clamp secured to the Witnesses:

the clamping pressure of the clamping plate is regulated.

In testimony whereof, I have signed my name to this specification, inthe presence of .two subscribing Witnesses.

FRED A. READ.

J. WARREN NICHOLS, THOMAS J. GANTY.

A fiopies o f't his patent may be obtained for five cents each, byaddressing the Commissioner of Patents,

7 Washington, D. C.

